diff --git a/Cargo.lock b/Cargo.lock
index 0fe31384274..894dcf937de 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -272,6 +272,7 @@ dependencies = [
  "atty",
  "bytesize",
  "cargo-test-macro",
+ "cargo-test-support",
  "clap",
  "core-foundation",
  "crates-io",
@@ -288,8 +289,9 @@ dependencies = [
  "git2",
  "git2-curl",
  "glob",
- "hex",
+ "hex 0.4.0",
  "home",
+ "humantime",
  "ignore",
  "im-rc",
  "jobserver",
@@ -329,6 +331,23 @@ dependencies = [
 name = "cargo-test-macro"
 version = "0.1.0"
 
+[[package]]
+name = "cargo-test-support"
+version = "0.1.0"
+dependencies = [
+ "cargo",
+ "cargo-test-macro",
+ "filetime",
+ "flate2",
+ "git2",
+ "glob",
+ "lazy_static 1.3.0",
+ "remove_dir_all",
+ "serde_json",
+ "tar",
+ "url 2.1.0",
+]
+
 [[package]]
 name = "cargo_metadata"
 version = "0.8.0"
@@ -700,7 +719,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09de9ee0fc255ace04c7fa0763c9395a945c37c8292bb554f8d48361d1dcf1b4"
 dependencies = [
  "commoncrypto",
- "hex",
+ "hex 0.3.2",
  "openssl",
  "winapi 0.3.6",
 ]
@@ -1262,6 +1281,12 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "805026a5d0141ffc30abb3be3173848ad46a1b1664fe632428479619a3644d77"
 
+[[package]]
+name = "hex"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "023b39be39e3a2da62a94feb433e91e8bcd37676fbc8bea371daf52b7a769a3e"
+
 [[package]]
 name = "home"
 version = "0.5.0"
@@ -2064,7 +2089,7 @@ dependencies = [
  "directories",
  "env_logger",
  "getrandom",
- "hex",
+ "hex 0.3.2",
  "log",
  "num-traits",
  "rand 0.7.0",
@@ -3259,6 +3284,7 @@ dependencies = [
  "serde",
  "serde_json",
  "smallvec",
+ "url 2.1.0",
  "winapi 0.3.6",
 ]
 
diff --git a/src/tools/cargo b/src/tools/cargo
index 9655d70af8a..3596cb86b2e 160000
--- a/src/tools/cargo
+++ b/src/tools/cargo
@@ -1 +1 @@
-Subproject commit 9655d70af8a6dddac238e3afa2fec75088c9226f
+Subproject commit 3596cb86b2e87dd9b9c1bb90d4a9d73ec2c1512f
diff --git a/src/tools/rustc-workspace-hack/Cargo.toml b/src/tools/rustc-workspace-hack/Cargo.toml
index 930279c0ca2..980c9753761 100644
--- a/src/tools/rustc-workspace-hack/Cargo.toml
+++ b/src/tools/rustc-workspace-hack/Cargo.toml
@@ -62,6 +62,7 @@ crossbeam-utils = { version = "0.6.5", features = ["nightly"] }
 serde = { version = "1.0.82", features = ['derive'] }
 serde_json = { version = "1.0.31", features = ["raw_value"] }
 smallvec = { version = "0.6", features = ['union', 'may_dangle'] }
+url = { version = "2.0", features = ['serde'] }
 
 
 [target.'cfg(not(windows))'.dependencies]